1. Field of the Invention
The present invention relates to a disc chucking mechanism and a disc drive apparatus having the same. Specifically, the present invention relates to a technical field in which a separation-stop shaft different from a central shaft that served as a motor shaft of a spindle motor is provided so as to secure a stable rotation operation of a disc chucking mechanism and make a disc drive apparatus thinner.
2. Description of the Related Art
A disc chucking mechanism for centering a disc-shaped recording medium and carrying out a chucking is provided in a disc drive apparatus that can record and reproduce an information signal to and from the disc-shaped recording medium, such as a optical disc, a magneto-optical disc and the like.
In the disc chucking mechanism, there is a type, in which a disc table and a chucking pulley are used to chuck the disc-shaped recording medium, and a centering protrusion of the disc table is pushed by a spring (for example, see Japanese Patent Application Publications 09-265705, 07-121239, 06-229158).
A disc chucking mechanism a has a disc table b and a chucking pulley c.
The disc table b is provided with a table section d, a centering protrusion e and a forcing spring f, and the center of the table section d is fixed to a central shaft g that served as the motor shaft of the spindle motor. An arrangement recessed portion h that is open upward is formed on the table section d.
The centering protrusion e is set in such a way that it is movably supported by the central shaft g in its shaft direction, and a part thereof is inserted into the arrangement recessed portion h of the table section d. On the outer circumference surface of the centering protrusion e, a guiding inclination surface i and a centering inclination surface j are formed from the upper side. In the guiding inclination surface i, the inclination angle with respect to the shaft direction of the central shaft g is set to be larger, for the centering inclination surface j.
The forcing spring f is the compressing coil spring and arranged between the table section d and the centering protrusion e in the arrangement recessed portion h. Thus, the centering protrusion e is pushed upward against the table section d by the forcing spring f.
A separation-stop ring k is attached in externally engaged manner at the position near the top end of the central shaft g. The contact of the separation-stop ring k with the upper surface of the centering protrusion e leads to the regulation of the upward movement of the centering protrusion e pushed by the forcing spring f. The top end of the central shaft g is upwardly protruded from the centering protrusion e and placed as a positioning section 1 that is approximately conically formed.
The chucking pulley c is placed as a pressing section m in which the portion on the outer circumferential side presses a disc-shaped recording medium x, and a downwardly opened and recessed portion n is formed on the inner side of the pressing section m. A positioning cylinder section o that is downwardly protruded and approximately cylindrical is placed on the recessed portion n, and the inner circumferential edge at the low end of the positioning cylinder section o is formed as a guided edge p. The guided edge p is inclined so as to be displaced to a direction closer to the outer surface of the positioning cylinder section o, as it goes down.
In the above-mentioned disc chucking mechanism a, when the centering protrusion e is inserted into a central hole y of the disc-shaped recording medium x, the chucking pulley c is lowered, and the inner circumferential section of the disc-shaped recording medium x is put between the table section d of the disc table b and the chucking pulley c, and the disc-shaped recording medium x is then chucked.
At this time, since the guided edge p of the positioning cylinder section o of the chucking pulley c is guided to the positioning section 1 of the central shaft g and the central shaft g is inserted into the positioning cylinder section o, the positioning between the disc table b and the chucking pulley c is done. At the same time, the inner circumferential edge of the disc-shaped recording medium x is brought into contact with the centering inclination surface j of the centering protrusion e. In association with the lowering of the chucking pulley c, the disc-shaped recording medium x and the centering protrusion e are moved together downward against the forcing force of the forcing spring f. Consequently, the positioning is performed on the central shaft g of the disc-shaped recording medium x.
When the disc-shaped recording medium x is chucked by the disc chucking mechanism a, the chucking pulley c is pressed and fitted to the disc-shaped recording medium x placed on the table section d. In conjunction with the rotation of the spindle motor, the disc table b, the chucking pulley c and the disc-shaped recording medium x are integrally rotated.
Furthermore, some of disc chucking mechanisms in the related art is configured to perform chucking operation of a disc-shaped recording medium with using guide holes extending in a shaft direction of the disc table (up-down direction), cam holes having an inclination section inclined with respect to the guide holes, and guide shafts being slidably engaged with the guide hole and the cam hole (see Japanese Patent Application Publication 06-180913, which will be referred to as Patent Document 1).
In such disc chucking mechanisms, a plurality of the guide hole (guide hole 103 in Patent Document 1), a plurality of the cam hole (guide hole 11 in Patent Document 1) and a plurality of the guide shaft (guide shaft 206 in Patent Document 1) are provided in such a way that they are separated from each other in front-back direction.
The disc-shaped recording medium placed on a disc tray is moved in the horizontal direction and inserted between a chucking pulley (clamp 209 in Patent Document 1) and the disc table (turn table 406 in Patent Document 1). Upon the insertion of the disc-shaped medium, a member having the cam holes (side plate 10 in Patent Document 1) is moved in the front-back direction so that the inclination section of the cam hole causes a change of position in the guide hole of the guide shaft. As a result, the chucking pulley is moved downward and the chucking operation of the disc-shaped recording medium with the chucking pulley and the disc table is completed.
The cam hole has an upper-side horizontal section being located on the upper side and extending in the front-back direction, a bottom-side horizontal section being located on the bottom side and extending in the front-back direction and the inclination section formed in between the upper-side horizontal section and the bottom-side horizontal section. Accordingly, the chucking pulley positions at the top when the guide shaft is engaged with the upper-side horizontal section. The chucking pulley moves downward when the guide shaft moves the inclination section from the upper-side horizontal section to the bottom-side horizontal section. The chucking pulley positions at the bottom when the guide shaft is engaged with the bottom-side horizontal section.